Warehouses, manufacturing facilities, large retail outlets and other buildings often include one or more loading docks for transferring goods and materials to and from trucks and trailers. Conventional loading docks typically include an elevated doorway or opening in an exterior side wall of a building. The opening is usually covered by a roll up door, and is typically positioned a few feet above the ground so that it will be approximately level with the beds of trucks and shipping trailers. The dock can include a dock leveler with a movable deck or ramp to adjust for any misalignment between the floor of the loading dock and the bed of the trailer. To load or unload goods from a trailer, the doors on the aft end of the trailer are opened and the trailer is backed up to the loading dock opening. After the dock leveler has been extended onto the trailer bed, workers, fork lifts, etc. can move into and out of the trailer to load or unload goods.
It is often desirable to seal any gaps that may exist between the open end of the trailer and the loading dock wall, as these gaps can allow rain, snow, or outside air to enter the building resulting in energy losses and/or undesirable working conditions. These gaps are typically sealed with either a dock seal or shelter that extends at least partially around the loading dock opening.
There are various types of loading dock enclosures that are used for sheltering and/or sealing the open end of a truck or trailer during the loading and unloading process. Such enclosures are described in, for example, U.S. patent application Ser. Nos.: 12/334,167 and 11/860,468; U.S. Pat. Nos.: 4,213,279; 4,601,142; 4,711,059; 4,718,207; 4,799,342; 4,885,881; 5,282,384; 5,953,868; and 6,311,435; U.S. Patent Publication Nos.: 2003/0177720 and 2004/0134139; International Patent Publication No. WO 2006/052661; and the Installation Instructions for the VSH Series Dock Seals, Form No. 4F-VSH-1/07, and the DSS & WM Series Dock Seals, Form No. 4F-DSS-1/07, both of which are available from 4Front Engineered Solutions, Inc., Muskego, Wis. 53150. The disclosures of the above-listed patents, patent applications and other documents are incorporated into the present disclosure in their entireties by reference.
Many conventional loading dock seals include resilient, compressible pads that are attached to the building along the lateral and top edges of the loading dock opening. The pads typically include a foam core covered with a coated vinyl fabric or other similar material for protection and appearance. In operation, the open trailer backs up against the seal and compresses the pads. The pads conform to the outer edge of the trailer opening as the trailer presses up against the pads, which helps seal the gap between the side of the building and the open trailer.
Wear and tear on dock seals from repeated compression by trailers can shorten the life of the seal. As the trailers compress the dock seal pads, the fabric covers can be punctured or otherwise damaged. Moreover, trailers with air-ride and other types of suspension can move up and down during loading/unloading. The abrasive forces from this movement can eventually wear through the fabric cover. If the fabric is punctured or torn, the foam core can be exposed to the elements and damaged by moisture, sunlight, etc. This can degrade the foam and impair the sealing capability of the pad, requiring costly and time consuming repairs or replacement.